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Chemical Communications (Cambridge,... Jul 2024A W-doped Pt modified graphene oxide (Pt-W-GO) electrochemical microelectrode was developed to detect hydrogen peroxide (HO) in real time at a subcellular scale....
A W-doped Pt modified graphene oxide (Pt-W-GO) electrochemical microelectrode was developed to detect hydrogen peroxide (HO) in real time at a subcellular scale. Interestingly, results showed that the concentration of HO in the nucleus of HeLa cells was 2.68 times and 0.51 times that in the extracellular membrane and cytoplasm, respectively.
PubMed: 38958176
DOI: 10.1039/d4cc02835j -
Journal of the American Heart... Jul 2024Endothelial cell (EC) dysfunction involves reduced nitric oxide (NO) bioavailability due to NO synthase uncoupling linked to increased oxidation and reduced cofactor...
BACKGROUND
Endothelial cell (EC) dysfunction involves reduced nitric oxide (NO) bioavailability due to NO synthase uncoupling linked to increased oxidation and reduced cofactor availability. Loss of endothelial function and NO bioavailability are associated with inflammation, including leukocyte activation. Eicosapentaenoic acid (EPA) administered as icosapent ethyl reduced cardiovascular events in REDUCE-IT (Reduction of Cardiovascular Events With Icosapent Ethyl-Intervention Trial) in relation to on-treatment EPA blood levels. The mechanisms of cardiovascular protection for EPA remain incompletely elucidated but likely involve direct effects on the endothelium.
METHODS AND RESULTS
In this study, human ECs were treated with EPA and challenged with the cytokine IL-6 (interleukin-6). Proinflammatory responses in the ECs were confirmed by ELISA capture of sICAM-1 (soluble intercellular adhesion molecule-1) and TNF-α (tumor necrosis factor-α). Global protein expression was determined using liquid chromatography-mass spectrometry tandem mass tag. Release kinetics of NO and peroxynitrite were monitored using porphyrinic nanosensors. IL-6 challenge induced proinflammatory responses from the ECs as evidenced by increased release of sICAM-1 and TNF-α, which correlated with a loss of NO bioavailability. ECs pretreated with EPA modulated expression of 327 proteins by >1-fold (<0.05), compared with IL-6 alone. EPA augmented expression of proteins involved in NO production, including heme oxygenase-1 and dimethylarginine dimethylaminohydrolase-1, and 34 proteins annotated as associated with neutrophil degranulation. EPA reversed the endothelial NO synthase uncoupling induced by IL-6 as evidenced by an increased [NO]/[peroxynitrite] release ratio (<0.05).
CONCLUSIONS
These direct actions of EPA on EC functions during inflammation may contribute to its distinct cardiovascular benefits.
PubMed: 38958135
DOI: 10.1161/JAHA.123.034076 -
Molecular Nutrition & Food Research Jul 2024Celiac disease (CD) is an allergic intestinal disease caused mainly by gliadin in wheat, which is widespread in the population and currently lacks effective treatment....
SCOPE
Celiac disease (CD) is an allergic intestinal disease caused mainly by gliadin in wheat, which is widespread in the population and currently lacks effective treatment. α-Gliadin peptides cause cellular damage by substantially increasing cellular reactive oxygen species (ROS) levels.
METHODS AND RESULTS
This study investigates the protective effect of 11 pea-derived peptides (PPs) on ɑ-gliadin peptide (P31-43) treated Caco-2 cells. Results show that cells treated with PP2, PP5, and PP6 peptides significantly reduce the cell mortality caused by P31-43. Three PPs significantly reduce the P31-43-induced decrease in ROS levels to control levels, and there is no difference between them and the vitamin C (Vc) group. The results in terms of antioxidant-related enzymes show that PPs significantly decrease superoxide dismutase activity (SOD), glutathione reductases (GR), and glutathione (GSH)/oxidized glutathione (GSSG) levels, thus significantly enhancing the antioxidant level of cells. By studying the key proteins of the Kelch-like ECH-associated protein 1 (Keap1)/NF-E2-related factor 2 (Nrf2) pathway, it is found that PPs activate the Keap1/Nrf2 signaling pathway.
CONCLUSION
The study finds that peptides from peas can effectively alleviate ɑ-gliadin peptide-induced cell damage. The discovery of these food-derived peptides provides novel potential solutions for the prevention and treatment of CD.
PubMed: 38958100
DOI: 10.1002/mnfr.202400010 -
Small (Weinheim An Der Bergstrasse,... Jul 2024In P2-type layered oxide cathodes, Na site-regulation strategies are proposed to modulate the Na distribution and structural stability. However, their impact on the...
In P2-type layered oxide cathodes, Na site-regulation strategies are proposed to modulate the Na distribution and structural stability. However, their impact on the oxygen redox reactions remains poorly understood. Herein, the incorporation of K in the Na layer of NaNiCuMnO is successfully applied. The effects of partial substitution of Na with K on electrochemical properties, structural stability, and oxygen redox reactions have been extensively studied. Improved Na diffusion kinetics of the cathode is observed from galvanostatic intermittent titration technique (GITT) and rate performance. The valence states and local structural environment of the transition metals (TMs) are elucidated via operando synchrotron X-ray absorption spectroscopy (XAS). It is revealed that the TMO slabs tend to be strengthened by K-doping, which efficiently facilitates reversible local structural change. Operando X-ray diffraction (XRD) further confirms more reversible phase changes during the charge/discharge for the cathode after K-doping. Density functional theory (DFT) calculations suggest that oxygen redox reaction in NaKNiCuMnO cathode has been remarkably suppressed as the nonbonding O 2p states shift down in the energy. This is further corroborated experimentally by resonant inelastic X-ray scattering (RIXS) spectroscopy, ultimately proving the role of K incorporated in the Na layer.
PubMed: 38958092
DOI: 10.1002/smll.202402991 -
Small (Weinheim An Der Bergstrasse,... Jul 20242D transition metal dichalcogenides (TMDCs) have been intensively explored in memristors for brain-inspired computing. Oxidation, which is usually unavoidable and...
2D transition metal dichalcogenides (TMDCs) have been intensively explored in memristors for brain-inspired computing. Oxidation, which is usually unavoidable and harmful in 2D TMDCs, could also be used to enhance their memristive performances. However, it is still unclear how oxidation affects the resistive switching behaviors of 2D ambipolar TMDCs. In this work, a mild oxidation strategy is developed to greatly enhance the resistive switching ratio of ambipolar 2H-MoTe lateral memristors by more than 10 times. Such an enhancement results from the amplified doping due to O and HO adsorption and the optimization of effective gate voltage distribution by mild oxidation. Moreover, the ambipolarity of 2H-MoTe also enables a change of resistive switching direction, which is uncommon in 2D memristors. Consequently, as an artificial synapse, the MoTe device exhibits a large dynamic range (≈200) and a good linearity (1.01) in long-term potentiation and depression, as well as a high-accuracy handwritten digit recognition (>96%). This work not only provides a feasible and effective way to enhance the memristive performance of 2D ambipolar materials, but also deepens the understanding of hidden mechanisms for RS behaviors in oxidized 2D materials.
PubMed: 38958086
DOI: 10.1002/smll.202402727 -
Small (Weinheim An Der Bergstrasse,... Jul 2024Residual alkali is one of the biggest challenges for the commercialization of sodium-based layered transition metal oxide cathode materials since it can even inevitably...
Residual alkali is one of the biggest challenges for the commercialization of sodium-based layered transition metal oxide cathode materials since it can even inevitably appear during the production process. Herein, taking O3-type NaNiMnFeMgTiO as an example, an active strategy is proposed to reduce residual alkali by slowing the cooling rate, which can be achieved in one-step preparation method. It is suggested that slow cooling can significantly enhance the internal uniformity of the material, facilitating the reintegration of Na into the bulk material during the calcination cooling phase, therefore substantially reducing residual alkali. The strategy can remarkably suppress the slurry gelation and gas evolution and enhance the structural stability. Compared to naturally cooled cathode materials, the capacity retention of the slowly cooled electrode material increases from 76.2% to 85.7% after 300 cycles at 1 C. This work offers a versatile approach to the development of advanced cathode materials toward practical applications.
PubMed: 38958079
DOI: 10.1002/smll.202403084 -
Small (Weinheim An Der Bergstrasse,... Jul 2024Nanofluidic ionic diodes have attracted much attention due to their unique functions as unidirectional ion transportation ability and promising applications from...
Nanofluidic ionic diodes have attracted much attention due to their unique functions as unidirectional ion transportation ability and promising applications from molecular sensing, and energy harvesting to emerging neuromorphic devices. However, it remains a challenge to fabricate diode-like nanofluidic systems with ultrathin film thickness <100 nm. Herein the formation of ultrathin ionic diodes from hybrid nanoassemblies of nanoporous (NP) SiO nanofilms and polyelectrolyte layer-by-layer (LbL) multilayers is described. Ultrathin ionic diodes are prepared by integrating polyelectrolyte multilayers onto photo-oxidized NP SiO nanofilms obtained from silsesquioxane-containing block copolymer thin films as a template. The obtained ultrathin ionic diodes exhibit ion current rectification (ICR) properties with high ICR factor = ≈20 under low ionic strength and asymmetric pH conditions. It is concluded that this ICR behavior arises from effective ion accumulation and depletion at the interface of NP SiO nanofilms and LbL multilayers attributed to high ion selectivity by combining the experimental data and theoretical calculations using finite element methods. These results demonstrate that the hybrid nano assemblies of NP SiO nanofilms and polyelectrolyte LbL multilayers have potential applications for (bio)sensing materials and integrated ionic circuits for seamless connection of human-machine interfaces.
PubMed: 38958070
DOI: 10.1002/smll.202404306 -
Small (Weinheim An Der Bergstrasse,... Jul 2024Acid-treated multi-walled carbon nanotube (MWCNT) covalently functionalized with cobalt triphenothiazine porphyrin (CoTriPTZ-OH) AB type porphyrin, containing three...
Acid-treated multi-walled carbon nanotube (MWCNT) covalently functionalized with cobalt triphenothiazine porphyrin (CoTriPTZ-OH) AB type porphyrin, containing three phenothiazine moieties (represented as MWCNT-CoTriPTZ) is synthesized and characterized by various spectroscopic and microscopic techniques. The nanoconjugate, MWCNT-CoTriPTZ, exhibits a pair of distinct redox peaks due to the Co/Co redox process in 0.1 M pH 7.0 phosphate buffer. Further, it electrocatalytically oxidizes hydrazine at a low overpotential with a high current. This property is advantageously utilized for the sensitive determination of hydrazine. The developed electrochemical sensor exhibits high sensitivity (0.99 µAµMcm), a low limit of detection (4.5 ppb), and a broad linear calibration range (0.1 µM to 3.0 mM) for the determination of hydrazine. Further, MWCNT-CoTriPTZ is exploited for hydrazine-assisted green hydrogen synthesis. The high efficiency of hydrazine oxidation is confirmed by the low onset potential (0.45 V (vs RHE)) and 0.60 V (vs RHE) at the current density of 10 mA.cm. MWCNT-CoTriPTZ displays a high current density (77.29 mA.cm) at 1.45 V (vs RHE).
PubMed: 38958069
DOI: 10.1002/smll.202401273 -
Histology and Histopathology Jun 2024Electroacupuncture (EA) pretreatment can effectively increase the tolerance of the brain to ischemic stroke. The mechanism of ischemic tolerance induced by EA is related...
OBJECTIVE
Electroacupuncture (EA) pretreatment can effectively increase the tolerance of the brain to ischemic stroke. The mechanism of ischemic tolerance induced by EA is related to Nrf2, but its specific mechanism has not been elucidated. This paper was designed to explore the effect of EA pretreatment on brain injury and the related mechanisms.
METHODS
Rats were pretreated with EA before middle cerebral artery occlusion (MCAO) modeling. The symptoms of neurological deficit and the volume of cerebral infarction were measured. The levels of inflammatory factors, oxidative stress-related factors, LPO, ROS, and Fe were evaluated by the corresponding kits. Cell apoptosis was determined through TUNEL staining. The mRNA expression of inflammatory factors was examined by RT-qPCR, and the protein expression of ferroptosis-related factors, pyroptosis-related proteins, Keap1, Nrf2, HO-1, and NQO1 by western blotting.
RESULTS
EA pretreatment improved the symptoms of neurological deficit and reduced the volume of cerebral infarction. EA pretreatment significantly inhibited oxidative stress, inflammatory response, ferroptosis, pyroptosis, and apoptosis in brain tissues of MCAO rats. Mechanistically, EA pretreatment could activate Nrf2 expression and reduce Keap1 expression.
CONCLUSION
EA pretreatment reduced inflammation and oxidative stress and inhibited ferroptosis by activating Nrf2 expression, ultimately delaying the development of ischemic stroke.
PubMed: 38958062
DOI: 10.14670/HH-18-780 -
Analytical Chemistry Jul 2024Nanoscale zinc-oxide doped with aluminum ZnO:Al is studied by different techniques targeting surface changes induced by the conditions at which ZnO:Al is used as support...
Nanoscale zinc-oxide doped with aluminum ZnO:Al is studied by different techniques targeting surface changes induced by the conditions at which ZnO:Al is used as support material in the catalysis of methanol. While it is well established that a variety of H and Al resonances can be found by solid-state NMR for this material, it was not clear yet which signals are related to species located close to the surface of the material and which to species located in the bulk. To this end, a method is suggested that makes use of a paramagnetically impregnated material to suppress NMR signals close to the particle surface in the blind sphere around the paramagnetic metal atoms. It is shown that it is important to use conditions that guarantee a stable reference system relative to which it can be established whether the coating procedure is conserving the original structure or not. This method, called paramagnetically assisted surface peak assignment, helped to assign the H and Al NMR peaks to the bulk and the surface layer defined by the blind sphere of the paramagnetic atoms. The assignment results are further corroborated by the results from heteronuclear Al{H} dipolar dephasing experiments, which indicate that the hydrogen atoms are preferentially located in the surface layer and not in the particle core.
PubMed: 38958037
DOI: 10.1021/acs.analchem.4c01170